title: Inter-bacterial correlations in subgingival biofilms: a large-scale survey.
abstract: OBJECTIVE
  Although the complexity of the oral ecology and the ecological differences between health and disease are well accepted, a clear view on the dynamics in relation to disease is lacking. In this study, the prevalence and abundance of 20 key oral bacteria was assessed in health and disease and more importantly a closer look was given to the inter-bacterial relationships.
  
  
  METHODS
  A blinded microbiological database was analysed in this cross-sectional, retrospective study. The database was constructed based on microbiological analyses of samples from 6308 patients, with gradations of periodontitis (healthy to periodontitis). Data concerning the abundance of 20 oral bacteria and probing pocket depth were provided.
  
  
  RESULTS
  Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Eubacterium nodatum, Porphyromonas micra and Porphyromonas intermedia showed a clear increase in abundance and prevalence with increasing pocket depth. Correlation matrices illustrated that almost all microorganisms were in one way correlated to other species and most of these correlations were significant. Several beneficial bacteria showed strong correlations with other beneficial bacteria.
  
  
  CONCLUSIONS
  Knowledge on bacterial correlations can pave the way for new treatment options focusing on restoring the shifted balance.
authors.affiliation: Department of Oral Health Sciences, KU Leuven & Dentistry, University Hospitals Leuven, Leuven, Belgium.
authors.forename: Gitte
authors.initials: G
authors.lastname: Loozen
authors.forename: Onur
authors.initials: O
authors.lastname: Ozcelik
authors.forename: Nico
authors.initials: N
authors.lastname: Boon
authors.forename: Antony
authors.initials: A
authors.lastname: De Mol
authors.forename: Christian
authors.initials: C
authors.lastname: Schoen
authors.forename: Marc
authors.initials: M
authors.lastname: Quirynen
authors.forename: Wim
authors.initials: W
authors.lastname: Teughels
mesh_terms: D000898:Antibiosis / Q000502:physiology; D001419:Bacteria / Q000145:classification* / Q000302:isolation & purification; D058491:Bacterial Load; D001439:Bacteroides / Q000302:isolation & purification; D018441:Biofilms; D003430:Cross-Sectional Studies; D019992:Databases as Topic; D003773:Dental Plaque / Q000382:microbiology*; D005051:Eubacterium / Q000302:isolation & purification; D005881:Gingiva / Q000382:microbiology*; D006801:Humans; D056265:Microbial Interactions; D010514:Periodontal Pocket / Q000145:classification / Q000382:microbiology*; D010518:Periodontitis / Q000145:classification / Q000382:microbiology*; D017861:Porphyromonas / Q000302:isolation & purification; D016966:Porphyromonas gingivalis / Q000302:isolation & purification; D018713:Prevotella intermedia / Q000302:isolation & purification; D012189:Retrospective Studies; D013291:Streptococcus / Q000302:isolation & purification; D048373:Treponema denticola / Q000302:isolation & purification
keywords: bacteria; ecology; microbiology; periodontitis